Borehole deflecting tool



April 20, 1943. w. F. WINGARD BOREHOLE DEFLECTING TOOL Filed July 25, 1940 mvzm-r o f I I WiLLlAM F. WINGARD, BY Jodi/ Patented Apr. 20, 1943 UNITED STATES PATENT OFFICE BOREHOLE DEFLECTING TOOL Wiliiam F. Wingard, Baltimore, Md.

Application July 25, 1940, Serial No. 347,441

I 8 Claims. (Cl. 255-16) This invention relates to borehole drilling apparatus and particularly to improved tools of the rotary drill type for changing the direction of the borehole when drilling for oil and the like.

In many instances it is desirable to deflect a borehole in a direction away from the vertical. Heretofore this has been accomplished by various types of apparatus such as knuckle joints, bent drill collars and fixed and removable bits. With many of these devices it is necessary to remove the drill from the borehole one or more times in order to make necessary adjustments in the apparatus to accomplish a change in direction. This is a tedious and expensive operation and it is advantageous to be able to change the direction of the bit while it is in the borehole.

The principal object of this invention is a rotary drill bit of novel construction operable to be deflected in any direction while cutting rotation is continuing and capable of control from the surface so as to move in the desired direction.

In accomplishing the purposes of this invention, a brake member is provided at the bottom of the bit disposed eccentrically of the center of the drill bit. In operation of the device to alter the direction of the bit the brake member is frictionally engaged with the bottom of the borehole. The bit tends to pivot about the brake member and is forced over to the side of the hole. A cutting edge on the side of the bit cuts into the wall of the hole on the side of the hole toward which the bit is urged. Frictional engagement between the brake member and the bottom of the borehole is released after the drill has revolved a predetermined number of degrees and the bit rotates normally. The brake member is then engaged again with the borehole bottom at the same point as before, forcing the bit in the same direction as before to engage the side wall. Thus, interrupted engagement of the brake member with the borehole at the same predetermined point in the orientation of the bit tends to deflect the bit thereby changing the direction of the hole.

For a full understanding of the invention, reference is to be had to the drawing and specification hereinbelow set forth.

Referring to the drawing, in which I have illustrated preferred embodiments of my inventlon:

Fig. 1 is a vertical sectional view of a borehole and showing a dril1 stem with my first form of drill bit;

Fig. 2 is a sectional view taken along the line 2-2 of Fi 1;

Figs. 3-7 are diagrammatic sectional views taken along the line 3-3 of Fig. 1 and showing the manner in which the bit is deflected;

Fig. 3 is a sectional View taken along the line 8--8 of Fig. 1 and showing the brake member in frictional engagement with the wall of the borehole; and

Fig. 9 is a sectiona1 View of a modified rock bit operable in a different way to accomplish the purpose of my first form.

Referring to the drawing, I have illustrated the principle of my invention by mechanical structure of relatively simple form. It is understood that the devices illustrated could be readily modified for commercial application without departing from the scope and spirit of the mechanical proposition shown therein.

Referring to Fig. 1 of the drawing, 1 have shown drilling apparatus in the act of cutting a borehole I. The drilling apparatus comprises a steel pipe or drill stem 2 and a rotary drill bit 3 connected to the stem 2 by a collar 4. The stem 2 is rotated by a power driven rotary table (not shown) and the stem imparts a rotary motion to the bit 3. The stem 2 has a circulation passage 5 so that water or mud can be pumped down through the stem to the drill bit and out into the borehole through holes (not shown) in the bit. By this method, material loosened by the bit is carried to the surface through the passage between the stem and the walls of the borehole.

The drill bit 3, with which I have chosen to illustrate the first form of my invention, is of the drag bit class providing a body 6 having four cutting wings I. It is understood, however, that (I do not wish to be limited by the particular form of drill bit illustrated and described as the principles of my invention are equally applicable to other types of bits.

As a means of obtaining the eccentric frictiona1 action for deflecting the drill bit, I nave provided a brake member which, in combination with a drill of the type illustrated, is in the form of a pin 8 normally disposed within the drill bit so as not to project beyond the lowermost end thereof. The pin 3 is disposed'in eccentric relation to the center of rotation of the drill bit. In the construction illustrated the pin has an angular arm ID at one end (Fig. 1) and the pin and arm are disposed within an opening i i of the bit body. The pin is movable within the opening H in a direction vertically of the borehole so as to pro ject beyond the limits of the drill bit at its lower end to frictionally engage the bottom wall 12 of the borehole when it is desired to deflect the bit. The pin member may be projected to engage the bottom wall [2 by any suitable mechanical, electrical or hydraulic means, but for purposes of simplicity I have chosen to illustrate a simple mechanical arrangement for accomplishing this result. Thus, I have provided a shaft i3 which is connected to the arm ill at one end and extends upwardly through the drill stem 2, as shown in Fig. 1. The upper end Id of the shaft is disposed above the surface and pressure may be applied to the same in any suitable way to press the shaft toward the bit so as to project the pin. In order to assure that the pin 8 will return to normal inoperative position automatically upon release of pressure on the shaft it, I have provided a coil spring it which surrounds the shaft near its lower end. One end of the spring 15 abuts the bottom wall it of a well in the upper end of the bit and an opposite end of the spring engages a collar it"; carried by the shaft. Intermediate the ends of the shaft it; I have provided a ball-andsocl;et joint is so that the shaft may assume a flexure angle after the borehole has been deflected in a direction which deviates from the vertical.

Operation of the pin member to deflect the drill may be most clearly understood from inspection of Figs. 3-7, wherein I have shown diagrammatically a possible cycle of operation. Referring to Fig. 3, the pin 3 is shown immediately after having been projected to engage the bottom wall E2 of the borehole. As a result of the fact that the pin is off from the center of the bit, the bit tends to pivot about the pin and consequently will be forced over to the side of the hole so as to cut the same. The pin may be held in projected position so as to drag irictionally against the bottom wall for approximately 90 of revolution of the unit, as shown in Fig. 4, and at this point pulled up to inoperative position and the drill allowed to complete its normal revolution. The pin is forced down at the same point as before during the second revolution, as shown in Fig. 6, and held down again for dragging engagement on the bottom wall i2 for approximately 90 rotation of ie bit, as shown in 7. Thus, pin may be projected at same point during each revolution of the bit until e borehole is deflected to the desired angle. After the borehole has been started in the desired direction, l is permitted to rotate normally whereby it the angle of deflection so as to continue the hole in the predetermined direction.

Referring to Fig. 9, I have shown a way in which the principle of my frictional brake memher is applicable to those classes of bits which de pend upon a cutting and chipping rather than a scraping action. These bits are particularly adaptable for cutting hard rock and frequently it is desirable to deflect a borehole which is being cut by one of these types of bits. Thus. I have shown in Fig. 9 a modified form of bit 20 of well known commercial design providing a body 2i having a hollow shank 22 at one end for threaded engagement with a drill collar. Side cutters 23 are attached to the sides of the body 21 and a number of cones 24, herein shown as two, are provided at the lower end of the biton the surfaces of which are milled a number of cutting teeth 25. In operation of the bit the cones, which are mounted relative to the body 2! on supporting pins 25, roll radially to chip the material at the bottom I2 of the borehole. It will be seen that, in view of the fact that the cones 24 are dis 11 Lire posed laterally of the center of rotation of the drill bit, any force tending to lessen the speed of rotation of one of the cones will cause the bit to tend to pivot on the cone so as to be urged toward a side of the borehole and cut the wall. Thus, if the rotating speed of one of the cones is checked at predetermined points in the revolutions of the drill bit, the cone will exert eccentric frictional engagement with the bottom of the borehole to accomplish the purpose of the pin 8 of the first application of my invention to deflect the drill bit in a desired direction. This braking action upon the cone could be accomplished by any suitable mechanical means, but I have shown an arrangement of simplest form in Fig. 9, wherein I have provided a bar 27 which is supported by a bearing 28 within the drill shank 22. The bar 21 is movable vertically of the borehole to engage its free end 29 with the pin 26 to lessen the speed of rotation of the pin. Operation of the bar to engage the pin at predetermined intervals in the rotation of the drill is controlled from the surface and any suitable mechanical means may be provided for moving the bar 2? into the said engagement.

Thus by my invention I have provided workable arrangements for accomplishing the desired objects. It is understood that the principles of my invention have been illustrated broadly by simple mechanical arrangements and that without departing from the scope and spirit of my invention it might be desirable to alter certain unimportant mechanical details substantially to efiect devices which would be suitable for commercial use. The broad principles, however, which are embodied in this invention should be clearly understood by the methods hereinabove shown and described.

Although I have illustrated and described preferred forms or my invention, I do not wish to. be limited thereby because the scope of my invention is best defined by the following claims.

I claim:

1. A device for changing the direction of a borehole comprising, in oombination,a rotatable drill stem, a drill afiixed to one end of said drill stem, and a pin mounted within sald'blt and disposed eccentrically of the center of rotation thereof, said pin being normally disposed in inoperative position within the periphery of said bit, said pin being p-rojectable beyond an end of said bit to engage the. bottom of said borehole, during rotation of said bit, and said'bit being pivotal about said projected pin during its rotation so as to be urged laterally relative to the longitudinal axis of said drill stem.

2. A device for changing the direction of a borehole comprising, in combination, a rotary drill stem having a bit at one end, and reciprocable brake means disposed eccentrically ,of the normal axis of rotation of the stem and Within the outer periphery of the bit for frictionally engaging a surface of said borehole during rotation of said bit, said brake when engaged with the surface of said borehole providing a. pivot for said bit eccentric to its central axis to urge the bit laterally relative to its normal axis of rotation. V

3. A device for changing the direction of :a'

portion of rotation of said bit, said brake when engaged with the surface of said borehole providing a pivot for said bit eccentric to its central axis to urge the bit laterally relative to its normal axis of rotation.

4. A device for changing the direction of a borehole comprising, in combination, a rotary drill stem having a bit at one end, and reciprocable brake means disposed eccentrically of the normal axis of rotation of the stem and within the outer periphery of the bit for frictionally engaging a surface of said borehole during rotation of said bit, said brake when engaged with the surface of said borehole providing a pivot for said bit eccentric to its central axis to urge the bit laterally relative to its normal axis of rotation, and means normally holding said brake means out of engagement with a surface of said borehole.

5. A device for changing the direction of a borehole comprising, in combination, a rotary drill stem having a bit at one end, and reciprocable brake means disposed eccentrically of the normal axis of rotation of the stem and within the outer periphery of the bit, said brake means being depressible to engage the bottom of the borehole during rotation of said bit, a vertically movable rod connected to said brake means and disposed in said drill stem for effecting depression of said brake means, and means for normally holding said brake means in an elevated inoperative position.

6. In combination with a rotatable drill bit and a hollow rotatable stem therefor, of a braking means reciprocally mounted within said bit, eccentric to the central vertical axis thereof, means for depressing said brake means to engage the bottom surface of the hole, being bored by said bit, during rotation thereof, to provide a temporary pivot for said rotatable bit eccentric to its previous axis of rotation.

7. In combination with a rotatable drill bit and a hollow rotatable stem therefor, of a braking means reciprocally mounted Within said bit eccentric to the central vertical axis thereof, means extending through said hollow stem for depressing said brake means to engage the bottom surface of the hole being bored by said bit, during rotation thereof, to provide a temporary pivot for said rotatable bit, eccentric to its previous axis of rotation.

8. In combination with a rotatable drill bit and a hollow rotatable stem therefor, of a braking means reciprocally mounted within said bit, eccentric to the central vertical axis thereof, means for depressing said brake means to engage the bottom surface of the hole being bored by said bit, during rotation thereof, to provide a temporary pivot for said rotatable bit, eccentric to its previous axis of rotation, and means normally acting to hold said brake means out of engagement with the bottom surface of the hole being bored.

WILLIAM F. WINGARD. 

